U.S. patent number 9,163,929 [Application Number 13/898,144] was granted by the patent office on 2015-10-20 for tomographic image generation apparatus having modulation and correction device and method of operating the same.
This patent grant is currently assigned to Korea Advanced Institute of Science and Technology, Samsung Electronics Co., Ltd.. The grantee listed for this patent is Korea Advanced Institute of Science and Technology, Samsung Electronics Co., Ltd.. Invention is credited to Hyun Choi, Jae-duck Jang, Woo-young Jang, Seong-deok Lee, Jae-guyn Lim, Yong-keun Park, Hyeon-seung Yu.
United States Patent |
9,163,929 |
Lim , et al. |
October 20, 2015 |
Tomographic image generation apparatus having modulation and
correction device and method of operating the same
Abstract
A tomographic image generation apparatus includes a light source
unit configured to emit light to be used for scanning an object; an
optical control unit configured to control a direction of
propagation of light; an optical coupler configured to divide and
combine incident light; a plurality of optical systems optically
connected to the optical coupler; and a modulation and correction
device configured to modulate and correct the light to be used for
scanning the object. The modulation and correction device may be
disposed between the optical control unit and the optical coupler,
or may be included in an optical system that irradiates light onto
the object among the plurality of optical systems. The modulation
and correction device may only modulate light that is reflected to
the object.
Inventors: |
Lim; Jae-guyn (Seongnam-si,
KR), Jang; Jae-duck (Daejeon, KR), Choi;
Hyun (Seoul, KR), Park; Yong-keun (Daejeon,
KR), Yu; Hyeon-seung (Daejeon, KR), Lee;
Seong-deok (Seongnam-si, KR), Jang; Woo-young
(Seongnam-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd.
Korea Advanced Institute of Science and Technology |
Suwon-si
Daejeon |
N/A
N/A |
KR
KR |
|
|
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-si, KR)
Korea Advanced Institute of Science and Technology (Daejeon,
KR)
|
Family
ID: |
49084757 |
Appl.
No.: |
13/898,144 |
Filed: |
May 20, 2013 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
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US 20140055789 A1 |
Feb 27, 2014 |
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Foreign Application Priority Data
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Aug 23, 2012 [KR] |
|
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10-2012-0092398 |
Nov 14, 2012 [KR] |
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10-2012-0129100 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
5/0066 (20130101); G01B 9/02091 (20130101) |
Current International
Class: |
G01B
9/02 (20060101); A61B 5/00 (20060101) |
Field of
Search: |
;356/479,497 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 417 789 |
|
Mar 2006 |
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GB |
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2007-199572 |
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Aug 2007 |
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JP |
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2009-3173 |
|
Jan 2009 |
|
JP |
|
10-2008-0014738 |
|
Feb 2008 |
|
KR |
|
10-2011-0036849 |
|
Apr 2011 |
|
KR |
|
WO 2010/014164 |
|
Feb 2010 |
|
WO |
|
Other References
IM. Vellekoop et al., "Phase control algorithms for focusing light
through turbid media, " Optics Communications, vol. 281, No. 11,
Jun. 1, 2008, pp. 3071-3080. cited by applicant .
Extended European Search Report issued on Nov. 18, 2013, in
counterpart European Application No. 13181509.4 (7 pages, in
English). cited by applicant.
|
Primary Examiner: Chowdhury; Tarifur
Assistant Examiner: Cook; Jonathan
Attorney, Agent or Firm: NSIP Law
Claims
What is claimed is:
1. A tomographic image generation apparatus comprising: a light
source unit configured to emit light to be used for scanning an
object; an optical control unit configured to control a direction
of propagation of light; an optical coupler configured to divide
and combine incident light; a plurality of optical systems
optically connected to the optical coupler; and a modulation and
correction device comprising an optical modulator and configured to
modulate and correct the light to be used for scanning the object;
wherein in the optical modulator, a reflection region of light that
enters from the optical coupler is different from a reflection
region of light that enters from the object.
2. The tomographic image generation apparatus of claim 1, wherein
the modulation and correction device is disposed between the
optical control unit and the optical coupler.
3. The tomographic image generation apparatus of claim 1, wherein
the plurality of optical systems comprise: a first optical system
configured to provide a reference light; and a second optical
system configured to irradiate light to the object.
4. The tomographic image generation apparatus of claim 3, wherein
the plurality of optical systems further comprise a third optical
system configured to receive an interference pattern, the
interference pattern generated by light generated from the first
optical system and light generated from the second optical
system.
5. The tomographic image generation apparatus of claim 3, wherein
the second optical system comprises the modulation and correction
device.
6. The tomographic image generation apparatus of claim 3, wherein
the second optical system comprises: a spatial light modulator
(SLM) configured to modulate light that enters from the optical
coupler; a galvanometer configured to reflect light that enters
from the SLM to the object and reflect light that enters from the
object to the SLM; and an object lens configured to focus light
that enters from the galvanometer onto the object.
7. The tomographic image generation apparatus of claim 6, wherein
the modulation and correction device is disposed between the second
optical system and the optical coupler.
8. The tomographic image generation apparatus of claim 3, wherein
the modulation and correction device is disposed between the
optical coupler and the second optical system.
9. The tomographic image generation apparatus of claim 1, wherein
the modulation and correction device comprises: the optical
modulator, configured to modulate only light that enters from the
optical coupler; and a grating configured to offset diffracted
light unnecessarily generated in the optical modulator.
10. The tomographic image generation apparatus of claim 9, wherein
the optical modulator corresponds to a first grating having a
plurality of grooves and the grating has a groove density that is
the same as a groove density of the first grating.
11. The tomographic image generation apparatus of claim 9, wherein
the optical modulator corresponds to a first grating having a
plurality of grooves and the grating has a groove density that is
different than a groove density of the first grating; and the
modulation and correction device further comprises a first lens and
a second lens disposed between the first grating and the grating
and configured to compensate for the difference in groove density
between the first grating and the grating.
12. The tomographic image generation apparatus of claim 9, wherein
the optical modulator is a digital micro-mirror device (DMD) or a
spatial light modulator (SLM).
13. The tomographic image generation apparatus of claim 1, wherein
the modulation and correction device comprises: the optical
modulator, configured to modulate light that enters from the
optical coupler; and a grating configured to offset diffracted
light unnecessarily generated from the optical modulator.
14. The tomographic image generation apparatus of claim 13, wherein
the optical modulator corresponds to a first grating having a
plurality of grooves and the grating has a groove density that is
different from a groove density of the first grating; and the
modulation and correction device further comprises a first lens and
a second lens disposed between the first grating and the grating
and configured to compensate for the difference in groove density
between the first grating and the grating.
15. The tomographic image generation apparatus of claim 14, wherein
the first optical system comprises two lenses corresponding to the
first and second lenses.
16. The tomographic image generation apparatus of claim 1, wherein
the modulation and correction device is disposed between the
optical coupler and the object.
17. The tomographic image generation apparatus of claim 1, wherein
the tomographic image generation apparatus is an optical coherence
tomography apparatus or an optical coherence tomography
microscope.
18. A method of operating a tomographic image generation apparatus,
the method comprising: emitting light from a light source to be
used for scanning an object; controlling a direction of propagation
of light using an optical control unit; dividing and combining
incident light through an optical coupler; modulating and
correcting, using a modulation and correction device comprising an
optical modulator, the light to be used for scanning the object;
and performing an optical modulation operation with respect to only
light that is reflected to the object using the optical modulator
of the modulation and correction device, wherein in the optical
modulator, a reflection region of light that enters from the
optical coupler is different from a reflection region of light that
enters from the object.
19. The method of claim 18, wherein the light that enters the
optical modulator from the optical coupler is incident to a first
region of the optical modulator; the light that enters the optical
modulator from the object is incident to a second region of the
optical modulator; the first and second regions are separated from
each other; and an optical modulation operation is performed only
in the first region.
20. The method of claim 18, further comprising performing the
modulating and correcting between the optical control unit and the
optical coupler.
21. The method of claim 18, further comprising performing the
modulating and correcting between the optical coupler and the
object.
22. The method of claim 18, further comprising configuring the
tomographic image generation apparatus to comprise a beam splitter
instead of the optical coupler.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Applications
No. 10-2012-0092398 filed on Aug. 23, 2012, and No. 10-2012-0129100
filed on Nov. 14, 2012, in the Korean Intellectual Property Office,
the disclosures of which are incorporated herein by reference in
their entirety.
BACKGROUND
1. Field
This application relates to tomographic image generation
apparatuses having a modulation and correction device that can
generate a more precise tomographic image by increasing a
penetration depth in an object and a magnitude of a signal
generated from the object, and methods of operating the same.
2. Description of Related Art
Tomography is a technique for capturing a tomographic image of an
object using a penetrating wave. Tomography is used in many fields.
Therefore, the demand for obtaining more precise tomographic images
is also increased. In particular, in medical fields that are
directly related to human life, a technique for generating a more
precise tomographic image is an important issue.
SUMMARY
In one general aspect, a tomographic image generation apparatus
includes a light source unit configured to emit light to be used
for scanning an object; an optical control unit configured to
control a direction of propagation of light; an optical coupler
configured to divide and combine incident light; a plurality of
optical systems optically connected to the optical coupler; and a
modulation and correction device configured to modulate and correct
the light to be used for scanning the object.
The modulation and correction device may be disposed between the
optical control unit and the optical coupler.
The plurality of optical systems may include a first optical system
configured to provide a reference light; and a second optical
system configured to irradiate light to the object.
The plurality of optical systems may further include a third
optical system configured to receive an interference pattern of
light generated from the first optical system and light generated
from the second optical system.
The second optical system may include the modulation and correction
device.
The second optical system may include a spatial light modulator
(SLM) configured to modulate light that enters from the optical
coupler; a galvanometer configured to reflect light that enters
from the SLM to the object and reflect light that enters from the
object to the SLM; and an object lens configured to focus light
that enters from the galvanometer onto the object.
The modulation and correction device may be disposed between the
second optical system and the optical coupler.
The modulation and correction device may be disposed between the
optical coupler and the first optical system.
The modulation and correction device may include an optical
modulator configured to modulate only light that enters from the
optical coupler; and a grating configured to remove diffracted
light unnecessarily generated in the optical modulator.
The grating may have a groove density that is the same as a groove
density of the optical modulator.
The grating may have a groove density that is different than a
groove density of the optical modulator; and the modulation and
correction device may further include a first lens and a second
lens disposed between the optical modulator and the grating and
configured to compensate for the difference in groove density
between the optical modulator and the grating.
In the optical modulator, a reflection region of light that enters
from the optical coupler may be different from a reflection region
of light that enters from the object.
The optical modulator may be a digital micro-mirror device (DMD) or
a spatial light modulator (SLM).
The modulation and correction device may include an optical
modulator configured to modulate light that enters from the optical
coupler; and a grating configured to remove diffracted light
unnecessarily generated from the optical modulator.
The grating may have a groove density that is different from a
groove density of the optical modulator; and the modulation and
correction device may further include a first lens and a second
lens disposed between the optical modulator and the grating and
configured to compensate for the difference in groove density
between the optical modulator and the grating.
The first optical system may include a lens corresponding to the
first and second lenses.
The modulation and correction device may be disposed between the
optical coupler and the object.
The optical coupler may be replaced by a beam splitter.
The tomographic image generation apparatus may be an optical
coherence tomography apparatus or an optical coherence tomography
microscope.
In another general aspect, a method of operating a tomographic
image generation apparatus includes a light source unit configured
to emit light to be used for scanning an object; an optical control
unit configured to control a direction of propagation of light; an
optical coupler configured to divide and combine incident light; a
plurality of optical systems optically connected to the optical
coupler; and a modulation and correction device configured to
modulate and correct the light to be used for scanning the object
and including an optical modulator; the method including performing
an optical modulation operation with respect to only light that is
reflected to the object using the optical modulator of the
modulation and correction device.
Light that enters the optical modulator from the optical coupler
may be incident to a first region of the optical modulator; light
that enters the optical modulator from the object may be incident
to a second region of the optical modulator; the first and second
regions may be separated from each other; and an optical modulation
operation may be performed only in the first region.
The modulation and correction device may be disposed between the
optical control unit and the optical coupler.
The modulation and correction device may be disposed between the
optical coupler and the object.
The tomographic image generation apparatus may include a beam
splitter instead of the optical coupler.
Other features and aspects will be apparent from the following
detailed description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an example of a configuration of a
tomographic image generation apparatus.
FIG. 2A is a cross-sectional view of an example of a configuration
of a second optical system of FIG. 1.
FIG. 2B is a perspective view showing an example of a case when a
region where light entering from an optical modulator to an optical
coupler is reflected and a region where light entering from an
object whose image is to be captured is reflected are
different;
FIG. 3 is a cross-sectional view of another example of a
configuration of a second optical system of FIG. 1.
FIG. 4 is a cross-sectional view of another example of a
configuration of a second optical system of FIG. 1.
FIG. 5 is a cross-sectional view of an example of a configuration
of a third optical system of FIG. 1.
FIG. 6 is a cross-sectional view of an example of a configuration
of a first optical system of FIG. 1.
FIG. 7 is a cross-sectional view of another example of a
configuration of a first optical system of FIG. 1.
FIGS. 8 and 9 are cross-sectional views showing examples of
elements of other examples of a tomographic image generation
apparatus.
FIG. 10 is a cross-sectional view of an example of a modified
version of the configuration of FIG. 9.
FIG. 11 is a cross-sectional view showing an example of a beam
splitter that is used instead of an optical coupler in a
tomographic image generation apparatus.
DETAILED DESCRIPTION
The following detailed description is provided to assist the reader
in gaining a comprehensive understanding of the methods,
apparatuses, and/or systems described herein. However, various
changes, modifications, and equivalents of the methods,
apparatuses, and/or systems described herein will be apparent to
one of ordinary skill in the art. The sequences of operations
described herein are merely examples, and are not limited to those
set forth herein, but may be changed as will be apparent to one of
ordinary skill in the art, with the exception of operations
necessarily occurring in a certain order. Also, description of
functions and constructions that are well known to one of ordinary
skill in the art may be omitted for increased clarity and
conciseness.
Throughout the drawings and the detailed description, the same
reference numerals refer to the same elements. The drawings may not
be to scale, and the relative size, proportions, and depiction of
elements in the drawings may be exaggerated for clarity,
illustration, and convenience.
FIG. 1 is a block diagram of an example of a configuration of a
tomographic image generation apparatus.
Referring to FIG. 1, the apparatus includes a light source unit 20,
a light control unit 22, and an optical coupler 24. Also, the
apparatus includes first, second, and third optical systems 30, 40,
and 50 connected to the optical coupler 24. The light source unit
20 emits light to be irradiated to an object whose tomographic
image is to be captured. The light source unit 20 may emit coherent
light. The light source unit 20 may include a light source that
emits coherent light.
As another example, the light source unit 20 may include a first
light source that emits non-coherent light, and an element that
transforms the non-coherent light emitted from the first light
source to coherent light.
A light source that is included in the light source unit 20 and
emits coherent light may be, for example, a laser diode. The first
light source that is included in the light source unit 20 and emits
non-coherent light may be, for example, a light-emitting diode
(LED). The element that transforms non-coherent light to coherent
light may be located between the light source unit 20 and the light
control unit 22. Light emitted from the light source unit 20 may
have a center wavelength of, for example, 1025 nm, and may have a
predetermined bandwidth with the center wavelength at the center of
the predetermined bandwidth. The light control unit 22 may be a
device that prevents the light emitted from the light source unit
20 from re-entering the light source unit 20 by being reflected by
other constituent elements of the apparatus. The optical coupler 24
may be a device that transmits light to the first and second
optical systems 30 and 40 by dividing light emitted from the light
source unit 20. Also, the optical coupler 24 may be a device that
transmits light to the third optical system 50 by combining light
entering from the first and second optical systems 30 and 40. The
splitting ratio of light divided in the optical coupler 24 to the
first and second optical systems 30 and 40 may be different from
each other. For example, in the optical coupler 24, an amount of
light divided to the second optical system 40 may be greater than
an amount of light divided to the first optical system 30. The
first optical system 30 may be an optical system that receives
light from the optical coupler 24 and reflects the light to the
optical coupler 24. This optical system may be connected to the
optical coupler 24. The first optical system 30 may provide a
reference light with respect to light to be processed in the second
optical system 40. Accordingly, the first optical system 30 may be
a reference optical system with respect to the second optical
system 40. The second optical system 40 receives light from the
optical coupler 24. The second optical system 40 may be connected
to the optical coupler 24. The second optical system 40 modulates
an amplitude or a frequency of light received from the optical
coupler 24, and then irradiates the modulated light onto an object
whose tomographic image is to be captured. The second optical
system 40 transmits light reflected by the object to the optical
coupler 24. The object whose tomographic image is to be captured
may be an organism that includes a plurality of cells. The object
whose tomographic image is to be captured may be a living organ,
for example, a skin of a living organ or a surface (an epidermis)
of an organ. The third optical system 50 may be a device that is
connected to the optical coupler 24 and generates tomography
information of an organ of the object. The tomography information
may be obtained from a combination of lights received from the
first and second optical systems 30 and 40 through the optical
coupler 24. Additionally, the third optical system 50 may record
tomography information of an organ of an object whose tomographic
image is to be captured. Configurations of the first through third
optical systems 30, 40, and 50 will be described below.
FIG. 2A is a cross-sectional view of an example of a configuration
of the second optical system 40 of FIG. 1. FIG. 2B is a perspective
view showing an example of a case when a region where light
entering from an optical modulator 40a to the optical coupler 24 is
reflected and a region where light entering from an object 60 whose
tomographic image is to be captured is reflected are different.
Referring to FIG. 2A, the second optical system 40 includes the
optical modulator 40a, a first grating 40b, first and second
mirrors 40c and 40d, and a first object lens 40e. The optical
modulator 40a and the first grating 40b may constitute a modulation
and correction device. The first and second mirrors 40c and 40d may
be disposed at a predetermined angle relative to each other, and
may rotate within a pre-set rotation range with respect to a given
center axis. The first and second mirrors 40c and 40d may
constitute a galvanometer. At this point, a driving element, for
example, a rotation motor (not shown) for driving the first and
second mirrors 40c and 40d may be further included. The optical
modulator 40a may be a device that modulates an amplitude or a
frequency of light (the solid lines) entering from the optical
coupler 24. The optical modulator 40a may include a plurality of
pixels. The pixels may form an array, and the pixels may have gaps
of, for example, approximately 10 .mu.m. The optical modulator 40a
may correspond to a grating having a plurality of groves. When a
gap between the pixels is approximately 10 .mu.m, the optical
modulator 40a may have a groove density corresponding to 100. The
groove density denotes a slit density (a number of slits per mm).
Each of the pixels performs as a wave source. A wavefront of light
(a plane wave) that enters the optical modulator 40a may be newly
configured by controlling the pixels of the optical modulator 40a.
Accordingly, light (the solid line) reflected at the optical
modulator 40a may have a wavefront that is different from that of
light that enters the optical modulator 40a. That is, light
reflected at the optical modulator 40a may have a pattern that is
different from that of light that enters the optical modulator 40a.
For the optical modulation as described above, pixels located on a
region where light enters the optical modulator 40a may be
controlled, and through this control, the pattern of incident light
may be modulated to be a desired pattern.
The optical modulator 40a does not perform an optical modulation
operation with respect to light (the dashed line) reflected by the
object 60. The optical modulator 40a performs an optical modulation
operation with respect to only light (the solid line) that enters
from the optical coupler 24.
More specifically, as depicted in FIG. 2B, light L11 incident to
the optical modulator 40a from the optical coupler 24 enters a
first region A1 of the optical modulator 40a. The first region A1
is a region where an optical modulation operation is performed.
Accordingly, the light L11 incident to the optical modulator 40a
from the optical coupler 24 is modulated and is reflected to the
first grating 40b.
Light L22 incident to the optical modulator 40a from the object 60
enters a second region A2 of the optical modulator 40a. The second
region A2 is separated from the first region A1. The second region
A2 is a region where an optical modulation operation is not
performed. Accordingly, the light L22 incident to the optical
modulator 40a from the object 60 is reflected to the optical
coupler 24 without any optical modulation.
The optical modulator 40a may be, for example, a digital
micro-mirror device (DMD) or a spatial light modulator (SLM). The
DMD includes a plurality of mirrors and each of the micro-mirrors
may perform as a pixel. Since the optical modulator 40a may perform
as a grating, a large amount of diffracted light may be generated
from the optical modulator 40a. A specific diffracted light of the
diffracted lights, for example, a fourth diffracted light, is used
for obtaining a tomographic image of the object 60. Accordingly,
diffracted lights that are not used for obtaining a tomographic
image of the object 60 may be diffracted light unnecessarily
generated, and to remove the diffracted light unnecessarily
generated, the second optical system 40 includes the first grating
40b. The first grating 40b may have a groove density (a slit
density) that is the same as that of the optical modulator 40a.
Therefore, a specific diffracted light generated from the optical
modulator 40a enters the object 60 and the diffracted light
unnecessarily generated may be removed. Thus, light may be
penetrated into a deeper region of the object 60, and thus a clear
tomographic image of a corresponding region may be obtained. The
first mirror 40c reflects light that is incident from the first
grating 40b to the second mirror 40d. An incidence angle of light
incident to the second mirror 40d may be controlled by controlling
the rotation angle of the first mirror 40c. The second mirror 40d
reflects light that enters from the first mirror 40c to the object
60. The reflection angle of light reflected at the second mirror
40d may be controlled by controlling the rotation angle of the
second mirror 40d, and, as a result, the incidence angle of light
(the solid line) incident to the object 60 may be controlled. The
incidence angle of light incident to the object 60 may be
controlled by controlling the rotation angles of the first and
second mirrors 40c and 40d. Therefore, optical scanning of light
with respect to the object 60 may be performed by controlling the
rotation angles of the first and second mirrors 40c and 40d. Light
(the solid line) reflected at the second mirror 40d is focused on
the object 60 through the first object lens 40e. Light (the dashed
line) reflected by the object 60 includes tomographic image
information of a scanned region of the object 60 and enters the
optical coupler 24 sequentially through the first object lens 40e,
the second mirror 40d, the first mirror 40c, the first grating 40b,
and the optical modulator 40a. Interference occurs between the
light that enters the optical coupler 24 from the optical modulator
40a and a reference light that enters from the first optical system
30, and a result of the interference (an interference pattern) is
transmitted to the third optical system 50.
FIG. 3 is a cross-sectional view showing another example of a
configuration of the second optical system 40 of FIG. 1. The
following description focuses on the differences between the second
optical system 40 of FIG. 3 and the second optical system 40 of
FIG. 2A. Like reference numerals are used to indicate substantially
identical elements.
Referring to FIG. 3, the second optical system 40 includes a second
grating 40h at the position of the first grating 40b in FIG. 2A.
The second grating 40h may have a groove density (a slit density)
that is different from that of the optical modulator 40a. The
second grating 40h may have a groove density smaller than that of
the optical modulator 40a, for example, the optical modulator 40a
may have a groove density of 400 that corresponds to a fourth
diffracted light, and the second grating 40h may have a diffraction
density of approximately 300 which is smaller than that of the
optical modulator 40a. First and second lenses 40f and 40g are
provided in parallel to each other between the optical modulator
40a and the second grating 40h to compensate for a difference in
groove density (diffraction density) of the optical modulator 40a
and the second grating 40h. The optical modulator 40a, the first
and second lenses 40f and 40g, and the second grating 40h may
constitute a modulation and correction device. The first and second
lenses 40f and 40g may be convex lenses and may have focal lengths
that are different from each other. For example, the first lens 40f
may have a focal length of 30 nm, and the second lens 40g may have
a focal length of 40 nm. The optical modulator 40a, the first lens
40f, the second lens 40g, and the second grating 40h may be
arranged on the same optical axis. The first and second lenses 40f
and 40g may be dual side convex lenses, but tare not limited
thereto.
FIG. 4 is a cross-sectional view of another example of a
configuration of the second optical system 40 of FIG. 1.
Referring to FIG. 4, the second optical system 40 includes a
spatial light modulator (SLM) 40i, the first and second mirrors 40c
and 40d, and the first object lens 40e. The spatial light modulator
40i reflects light (the solid line) that enters from the optical
coupler 24 to the first mirror 40c. The progress of light after the
first mirror 40c is the same as the progress described above. After
the light is scanned onto the object 60, light (the dashed line)
reflected by the object 60 enters the optical coupler 24 via the
first object lens 40e, the second mirror 40d, the first mirror 40c,
and the spatial light modulator 40i.
FIG. 5 is a cross-sectional view of an example of a configuration
of the third optical system 50 of FIG. 1.
Referring to FIG. 5, the third optical system 50 includes a third
grating 50a, a third lens 50b, and an optical image sensing device
50c. Light L2 that enters from the optical coupler 24 includes
information of a tomographic image of a given depth of the object
60, and enters the optical image sensing device 50c sequentially
through the third grating 50a and the third lens 50b. The third
grating 50a may have a slit density of, for example, 1200 lines/mm.
The optical image sensing device 50c recognizes a tomographic image
included in the light L2, and may be, for example, a charge-coupled
device (CCD).
FIG. 6 is a cross-sectional view of an example of a configuration
of the first optical system 30 of FIG. 1.
Referring to FIG. 6, the first optical system 30 includes a second
object lens 30a and a third mirror 30b which has the same optical
axis as the second object lens 30a. The second object lens 30a may
be the same object lens 40e of FIG. 2A. Light (the solid line)
incident from the optical coupler 24 enters the third mirror 30b
through the second object lens 30a. After being reflected by a
surface of the third mirror 30b, the light is incident to the
optical coupler 24 through the second object lens 30a. An optical
path from the optical coupler 24 to the third mirror 30b may be the
same as the optical path from the optical coupler 24 to the object
60. Accordingly, a tomographic image corresponding to a
predetermined depth of the object 60 may be obtained through an
interference pattern of light (a reference light) that is divided
with respect to the first optical system 30 and light that is
divided with respect to the second optical system 40 to scan the
object 60 to a predetermined depth.
FIG. 7 is a cross-sectional view of another example of a
configuration of a first optical system 30 of FIG. 1. The
configuration of the first optical system 30 of FIG. 7 corresponds
to the second optical system 40 of FIG. 3.
Referring to FIG. 7, the first optical system 30 includes fourth
and fifth lenses 30c and 30d which have the same optical axis, a
second object lens 30a, and a third mirror 30b. The fourth and
fifth lenses 30c and 30d are arranged between the optical coupler
24 and the second object lens 30a. Light (the solid line) that
enters from the optical coupler 24 enters a third mirror 30b
through the fourth lens 30c, the fifth lens 30d, and the second
object lens 30a, and light (the dashed line) reflected by the third
mirror 30b enters the optical coupler 24 sequentially through the
second object lens 30a, the fifth lens 30d, and the fourth lens
30c.
FIG. 8 is a cross-sectional view showing examples of elements of
another example of a tomographic image generation apparatus. The
following description focuses on the differences between the
apparatus of FIG. 1 and the apparatus of FIG. 8. Like reference
numerals are used to denote substantially identical elements.
Referring to FIG. 8, the apparatus includes the modulation and
correction device of FIG. 2A, that is, the optical modulator 40a
and the first grating 40b, between the optical control unit 22 and
the optical coupler 24. In the apparatus, light L3 emitted from the
optical control unit 22 is reflected at a fourth mirror 70, and
then enters the optical modulator 40a. Light L4 modulated in the
optical modulator 40a enters the first grating 40b. The modulated
light L4 is reflected at the first grating 40b and enters a fifth
mirror 72. The configuration of the second optical system 40 of the
apparatus of FIG. 8 may be the same as that of the second optical
system 40 of FIG. 2A when the optical modulator 40a and the first
grating 40b are removed.
Meanwhile, in FIG. 8, to change an optical path between the optical
control unit 22 and the optical modulator 40a, at least one more
mirror besides the fourth mirror 70 may be included. That is, at
least one mirror besides the fourth mirror 70 may be further
included between the optical control unit 22 and the optical
modulator 40a.
Also, at least one mirror besides the fifth mirror 72 may be
further included between the first grating 40b and the optical
coupler 24.
FIG. 9 is a cross-sectional view showing examples of elements of
another example of a tomographic image generation apparatus. The
following description will focus on the differences between the
apparatus of FIG. 1 and the apparatus of FIG. 9. Like reference
numerals are used to indicate substantially identical elements.
Referring to FIG. 9, the apparatus includes the fourth and fifth
mirrors 70 and 72 between the optical control unit 22 and the
optical coupler 24, and includes the modulation and correction
device of FIG. 3, that is, the optical modulator 40a, the first and
second lenses 40f and 40g, and the second grating 40h, between the
fourth and fifth mirrors 70 and 72. Light L3 emitted from the
optical control unit 22 is reflected at the fourth mirror 70 and
enters the optical modulator 40a. Light L4 modulated at the optical
modulator 40a enters the second grating 40h sequentially passing
through the first and second lenses 40f and 40g. The light L4 that
entered the second grating 40h is reflected at the fifth mirror 72
and enters the optical coupler 24. In the apparatus of FIG. 9, the
configuration of the second optical system 40 may be the same as
that of the second optical system 40 of FIG. 3 when the optical
modulator 40a, the first and second lenses 40f and 40g, and the
second grating 40h are removed.
In FIG. 9, to change an optical path between the optical control
unit 22 and the optical modulator 40a, at least one more mirror
besides the fourth mirror 70 may be included. That is, at least one
mirror besides the fourth mirror 70 may be further included between
the optical control unit 22 and the optical modulator 40a.
Also, at least one mirror besides the fifth mirror 72 may be
further included between the second grating 40h and the optical
coupler 24.
FIG. 10 is a cross-sectional view of an example of a modified
version of the configuration of FIG. 9.
Referring to FIG. 10, instead of the fourth mirror 70 of FIG. 9, a
light source 25 connected to the optical control unit 22 may be
used. Light having a plane wave generated from the light source 25
may enter the optical modulator 40a. The optical control unit 22
and the light source 25 may be connected to each other using an
optical transmission medium 23, which may be, for example, an
optical fiber.
Also, a sixth mirror (not shown) may be included between the fifth
mirror 72 and the optical coupler 24. At this point, the sixth
mirror may reflect light that is reflected by the fifth mirror 72
to the optical coupler 24. At least one mirror besides the fifth
mirror 72 and the sixth mirror may be further included between the
second grating 40h and the optical coupler 24.
FIG. 11 is a cross-sectional view of an example of a beam splitter
45 that is used instead of the optical coupler 24 in a tomographic
image generation apparatus. Light that enters the beam splitter 45
from the optical control unit 22 is divided with respect to the
first and second optical systems 30 and 40. Lights that enter the
beam splitter 45 from the first and second optical systems 30 and
40 are combined and transmitted to the third optical system 50.
Light that is transmitted to the third optical system 50 from the
beam splitter 45 may be transmitted by an optical transmission
medium such as an optical fiber.
In FIG. 11, a modulation and correction device described with
reference to FIGS. 8 through 10 may be included between the optical
control unit 22 and the beam splitter 45.
Meanwhile, in the apparatuses of FIGS. 1, 8, and 9, the elements
may be spatially separated on the same optical axis, may be
connected to each other using an optical transmission medium, or
may be configured without an optical transmission medium. The
optical transmission medium may be, for example, an optical fiber
or a waveguide.
When the elements are configured without an optical transmission
medium, the elements are in a spatially separated state arranged on
an optical axis. Accordingly, light emitted from an element, for
example, the beam splitter 45, may directly enter another element,
for example, the second optical system 40.
In the examples described above, a tomographic image generation
apparatus may be an optical coherence tomography apparatus or an
optical coherence tomography microscope.
While this disclosure includes specific examples, it will be
apparent to one of ordinary skill in the art that various changes
in form and details may be made in these examples without departing
from the spirit and scope of the claims and their equivalents. The
examples described herein are to be considered in a descriptive
sense only, and not for purposes of limitation. Descriptions of
features or aspects in each example are to be considered as being
applicable to similar features or aspects in other examples.
Suitable results may be achieved if the described techniques are
performed in a different order, and/or if components in a described
system, architecture, device, or circuit are combined in a
different manner and/or replaced or supplemented by other
components or their equivalents. Therefore, the scope of the
disclosure is defined not by the detailed description, but by the
claims and their equivalents, and all variations within the scope
of the claims and their equivalents are to be construed as being
included in the disclosure.
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